A Multicistronic DNA Vaccine Induces Significant Protection against Tuberculosis in Mice and Offers Flexibility in the Expressed Antigen Repertoire.

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1 Company LOGO A Multicistronic DNA Vaccine Induces Significant Protection against Tuberculosis in Mice and Offers Flexibility in the Expressed Antigen Repertoire. Fayaz Ahmad Mir, Stefan H. E. Kaufmann, and Ali Nasser Eddine Clinical and Vaccine Immunology 16(10): , Speaker: I Lun Chiang Advisor: Ching Tsan Huang Date:

2 The Development of Vaccines Live attenuated ex: BCG, measles Inactivated (killed) ex: polio, hepatitis A Contain only fragments (subunits) of the pathogen ex: tetanus, diphtheria toxoid genetically engineered vector coding antigen gene ex: HIV DNA vaccine 2

3 Whole-organism Vaccines Live attenuated vaccines: uses pathogens that are living but have reduced virulence. contain replicating microbes that can stimulate a strong immune response. Risk of reversion to pathogenicity Inactivated (killed) vaccines: safer than live vaccinesthey cannot replicate or mutate to a virulent form Multiple dose typically required Adjuvants normally needed 3

4 Subunit Vaccines Protein-based vaccines nucleic acid of the pathogen has been removed, only protein subunits remain. the subunits have less risk of causing adverse reactions. need to be administered with a potent adjuvant. 4

5 DNA Vaccines DNA vaccines use episomal vectors expressing antigens under eukaryotic promoters in the vaccinated host. can elicit potent humoral and cellular immune responses comprising both CD4+ and CD8+ T cells. (Adapted from Wikipedia) 5

6 DNA vaccines generate antigen inside the cell Humoral response T cell response Free Ag MHC1 antigenic peptides 6

7 The Efficacy of DNA Vaccines Strategies to improve the efficacy of DNA vaccination: vector backbone DNA sequence -strong promoter ex: CMV promoter, SV40 promoter transgene sequence -antigen co-expression of stimulatory sequences ex: adjuvants delivery system used for the vector Review- Genetic vaccine and Therapy (2003) 7

8 Strong promoters: CMV & SV40 Review- Genetic vaccine and Therapy (2003) 8

9 Delivery methods of DNA Vaccines Injection Aqueous solution in saline - intramuscularly (i.m.) Injection Gene gun DNA-coated gold beads -intradermally (i.d.) Gene gun Genetic vaccines (1999) Scientific American 281 (1):

10 DNA Vaccines Development DNA vaccine technology is showing increasing promise in the treatment of disease in humans Numerous animal models are under investigation for the use of DNA vaccines in humans Malaria AIDS Herpes Rotavirus (childhood diarrhea) Tuberculosis 10

11 Tuberculosis (TB) Tuberculosis (TB) is a disease mainly caused by Mycobacterium tuberculosis. 11

12 Infection Pathways of TB in Human spread through the air form granulomas in the lung Chronic infection 12

13 Milestones in TB History Nature Review : Immunology (2006) They developed Mycobacterium bovis bacillus Calmette-Guérin (BCG ) in

14 Bacillus Calmette-Guérin (BCG) Vaccine live attenuated Mycobacterium bovis bacillus BCG provides some useful level of protection against childhood TB. BCG provides little or no protection against adult pulmonary TB. 14

15 The safety and efficacy of BCG emphasize the need for alternative TB vaccines. 1. Live vaccines - Attenuated Mycobacteria tuberculosis - Recombinant BCG 2. Subunit vaccines - secreted antigen proteins - cell-bound antigen proteins - surface exposed antigens 15

16 Current Subunit Vaccines against TB Secreted antigens: - CFP-10, ESAT-6, Ag85B, Ag85A Dormancy antigens: - HspX, Hsp65, Hsp70 Resuscitation antigens: - Rv3407 Mollenkopf, H. J. et al. (2004) Olsen, A. W. et al. (2004) Roupie, V. et al.(2007) Polyprotein: fusion of M. tuberculosis antigens - ESAT6 + Ag85B Olsen, A. W. et al. (2004) - Mtb72F: Mtb39A + Mtb32C Skeiky, Y. A. et al. (2004) 16

17 Stages of M. tuberculosis infection Secreted antigens Dormancy antigens Granuloma Resuscitation antigens 17

18 Multicistronic DNA Vaccine Multicistronic DNA vaccine - DNA plasmid coding multiple antigens 18

19 Multicistronic Strategies Fusion proteins Bidirectional promoters Internal ribosomal entry site (IRES) 2A peptide sequence Ibrahimi, A. et.al (2009) Hum Gene Therapy 20(8):

20 2A Peptide sequence Picornaviruses, such as poliovirus and foot-and-mouth disease virus (FMDV), encode all of their proteins within a single open reading frame (ORF) In the case of the FMDV, the 18 aa. 2A region has a major role in polyprotein processing. 20

21 Mechanism of 2A Self-cleavage Co-translational, intraribosomal cleavage of polypeptides by FMDV 2A peptide The FMDV 2A sequence functions during co-translational translocation. Protein sequences following 2A are excluded from the ER lumen. (de Felipe et al. (2003) JBC 278:13 p ) 21

22 Vector Construction Cytomegalovirus (CMV) 22

23 Transfection of HEK293T cells Transfection reagent lipofectamine V-2A DNA pcmv.tp A DNA-lipofectamine complex transfection HEK293T cells ELISA 72 hour Collect the cells 23

24 Protein coexpression by V-2A multicistronic vector Control vector Western blotting analysis V-2A pcmv-tpa monocistronic vector pcmv-tpa -Rv

25 Coexpression of four proteins transfection Control vector monocistronic vector multicistronic vector 48 h pcmv-tpa pcmv-tpa -GFP HEK293T cells Fluorescent microscopy Expression of active Green fluorescence 25

26 Quantification of expression levels quantitative RT-PCR SYBR green - dsdna dye GADPH -internal control No significant difference in Ct value monocistronic pcmv-tpa -Rv3407 multicistronic V-2A 26

27 Cellular and Humoral Immune Response after DNA Vaccination Humoral response IFN-γ TNF-α IL-2 Th1 Response 100 μg DNA IgG1 IgG2a BALB/c mice 27

28 Cellular Immune Response induce by V-2A * P < 0.05 ** P < 0.01 *** P <

29 Cellular Immune Response induce by V-2A Lymph node Spleen * P < 0.05 ** P < 0.01 *** P <

30 Humoral Immune response induced by V-2A Antibody titers were measured by ELISA * P < 0.05 ** P <

31 Protective efficacy after Aerosol Challenge V-2A vaccination 4 weeks Aerosol challenge 10 6 CFU M. tuberculosis CFU counting of lung tissuue BCG vaccination 90 days BALB/c mice * P < 0.05 ** P <

32 Summary In vitro V-2A-GFP Western Fluorescence microscopy quantitative RT-PCR Protein expression levels are equal V-2A Cellular Immune response In vivo Humoral Immune response Protective efficacy against TB V-2A is an effective DNA vaccine Multicistronic DNA Vaccine may be a potential treatment for TB 32

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